Pennsylvania is home to one of the quirkiest delegate systems on the Republican nominating schedule.
The state will be electing 54 delegates who are "unbound," in addition to the 17 bound delegates who must vote for the statewide winner on the first ballot. The 54 unbound delegates are free to vote for whomever they choose at the July convention.
Many have committed to vote for either GOP frontrunner Donald Trump or Ted Cruz, the Texas senator looking to secure the Republican nomination on a second ballot at the convention.
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But many other potential delegates remain uncommitted or have pledged to vote along with how their congressional district or their state as a whole votes. Three unbound delegates will be elected in each of Pennsylvania's 18 congressional districts.
To show how volatile those pledges can be — they're not at all binding — take Mark Holt of the state's 10th District as an example.
On Monday, Holt — who previously told reporters, as well as Business Insider, that he leaned toward supporting Trump but favored the popular vote of his congressional district — came out in support of Cruz.
Here's what he said in an email to Business Insider explaining his process:
It has been reported that I support Mr. Trump, when I favored the [popular] vote of the people for my choice.
Then it was reported that I was uncommitted (made no choice) when I still favored the [popular] vote of the people.
Then the Trump people called me and told me they were going to endorse three candidates and I didn't make the cut !
An endorsement from these powerful political machines can make or break a campaign, and I just lost one by my favoring the [popular] option instead of the endorsement option. My bad.
[On] 4/22 The Cruz campaign was in town. They ask[ed] me to meet with the Senator. I did. We talked. I was impressed by him.
[On] 4/23 The Cruz campaign ask[ed] me to endorse Senator Cruz. I said Yes because he sold me the day before when we spoke.
Also I have two platform concerns about Mr. Trump. One is his love of eminent domain.
The other is his mixed message on abortion and the right to life of unborn babies.
After serious consideration and many phone calls requesting me to support or endorse a candidate, I have concluded that Senator Cruz meets my expiations [sic] for a President. I admire both men but feel more comfortable with the Senator. Therefore as of 4/24/2016 12:00 pm I endorse Senator Cruz for President of The United States of America.
The voters want to know who each delegate will support to that end: I have picked Senator Cruz !
When voters head to the polls to cast ballots for the delegates of their choosing, they will be presented with a list of choices for their congressional district. But the preferences and pledges of the candidates will not be available.
The change of opinion from Holt, which happened over the course of just a couple of days, also shows how the delegates, once elected, could change their minds a number of times in the three months before the July convention.
Based on recent projections, Pennsylvania's unbound delegates could make the difference in whether Trump lands the GOP nomination on the first ballot or is thwarted, opening up a second ballot and possibly more.